The Southern California Association of Governments (SCAG) is the designated metropolitan planning organization (MPO) under federal law, responsible for developing and adopting a long-range Regional Transportation Plan (RTP). Also, pursuant to the California’s Sustainable Communities and Climate Protection Act (SB 375), which is the nation’s first law to control Greenhouse Gas (GHG) emissions, SCAG is required to include a Sustainable Communities Strategy (SCS) as an element of the RTP to address how the region will meet the GHG emission targets by aligning transportation, housing and regional land use plans with GHG emission reductions.

In compliance with the requirements, SCAG developed an innovative parcel-based sketch planning model (PSM) which analyzed the impact of different land use scenarios on vehicle ownership, vehicle miles traveled (VMT), and GHG emissions, in preparation for the 2012-2035 Regional Transportation Plan/Sustainable Communities Strategy (2012-2035 RTP/SCS). As SB 375 encourages a transit-oriented development (TOD) as a land use approach to reduce GHG emissions, SCAG developed a TOD land use alternative as a preferred plan scenario for the 2012-2035 RTP/SCS. The PSM was able to accurately estimate vehicle miles travelled that is proportional to the GHG emissions for different land use scenarios.

The objective of this research is to demonstrate how we integrated PSM with GIS in order to measure the impacts of land use scenario on travel behavior and GHG emissions. As input data for the PSM, SCAG used the ArcGIS to process parcel data to create a ¼ mile buffer for each household in the 2009 National Household Travel Survey. SCAG also used ArcGIS to process household density, employment density, mixed use, street density (walkability index) and transit access, etc., within the buffer. In addition, ArcGIS was used to visualize effectively the spatial patterns of model input data and results, using data visualization tools and spatial statistics tools. The PSM was effectively used for the 2012-2035 RTP/SCS as a statistical model within a GIS framework.